Bernstein H G, Keilhoff G, Seidel B, Stanarius A, Huang P L, Fishman M C, Reiser M, Bogerts B, Wolf G
Department of Psychiatry, University of Magdeburg, Germany.
Neuroendocrinology. 1998 Dec;68(6):403-11. doi: 10.1159/000054390.
The gas nitric oxide (NO) is an important messenger in brain signaling. Along with many other functions, NO is thought to influence the expression and/or release of various hypothalamic hormones (corticotropin-releasing hormone (CRH), gonadotropin-releasing hormone (GnRH) and vasopressin). To learn more about the role of NO in neuroendocrine mechanisms, we studied in mutant mice lacking neuronal isoform of NO synthase (nNOS) the cellular expression of CRH, neurophysin (the carrier protein of vasopressin/oxytocin) and pro-opiomelanocortin (POMC), as well as of the POMC-derived peptides beta-endorphin (beta-END), alpha-melanocyte-stimulating hormone (alpha-MSH) and corticotropin (ACTH) by use of immunohistochemistry and in situ hybridization. Additionally, the remaining NO-generating capacities of the nNOS minus mice were investigated by NADPH-diaphorase histochemistry and citrulline immunohistochemistry as well as by immunohistochemical localization and Western blot analysis of endothelial NOS (eNOS) and nNOS isoforms. Amongst all hypothalamic peptides under investigation, only beta-END was found to be altered in mutant mice. A morphometric analysis of beta-END producing neurons of the arcuate nucleus revealed that significantly less cells were immunoreactive in mutant mice, whereas the expression of the precursor POMC as well as of other POMC-derived peptides was found to be unchanged. In addition to that, fewer beta-END-immunoreactive fibers were found in the paraventricular nucleus of nNOS minus mice in comparison to wild-type animals. Hence, the reduction of hypothalamic beta-END is probably a posttranslational event that might reflect a disturbed endorphinergic innervation of those hypothalamic neurons which normally express nNOS.
气体一氧化氮（NO）是脑信号传导中的一种重要信使。除了许多其他功能外，NO被认为会影响各种下丘脑激素（促肾上腺皮质激素释放激素（CRH）、促性腺激素释放激素（GnRH）和血管加压素）的表达和/或释放。为了更多地了解NO在神经内分泌机制中的作用，我们在缺乏神经元型一氧化氮合酶（nNOS）的突变小鼠中，通过免疫组织化学和原位杂交研究了CRH、神经垂体素（血管加压素/催产素的载体蛋白）和阿片促黑素皮质素原（POMC）以及POMC衍生肽β-内啡肽（β-END）、α-黑素细胞刺激素（α-MSH）和促肾上腺皮质激素（ACTH）的细胞表达。此外，通过NADPH-黄递酶组织化学、瓜氨酸免疫组织化学以及内皮型一氧化氮合酶（eNOS）和nNOS亚型的免疫组织化学定位和蛋白质免疫印迹分析，研究了nNOS基因敲除小鼠剩余的NO生成能力。在所有研究的下丘脑肽中，仅发现突变小鼠中的β-END发生了改变。对弓状核中产生β-END的神经元进行形态计量分析发现，突变小鼠中免疫反应性细胞明显减少，而前体POMC以及其他POMC衍生肽的表达未发生变化。除此之外，与野生型动物相比，在nNOS基因敲除小鼠的室旁核中发现的β-END免疫反应性纤维较少。因此，下丘脑β-END的减少可能是一种翻译后事件，这可能反映了那些正常表达nNOS的下丘脑神经元的内啡肽能神经支配受到了干扰。
